Divide students into small groups and provide each group with a board game to play. If there is time, rotate the groups to different games. Small groups of students can also be provided with puzzles to assemble. Use a game like Bingo as a whole group activity. Many other games can be organized quickly and require little to no materials. Classic games like charades, 7-Up, Duck Duck Goose, Simon Says and 20 Questions can fill time.
Pack a variety of work sheets in your substitute teacher folder that can be used for different grades. Photocopy enough pages so that you can quickly pull them out when needed with no preparation required. Crossword puzzles, word searches, mazes, coloring pages, word jumbles and connect-the-dot pages are enjoyable activities that can fill time. Provide students with themed worksheets to coincide with the season or upcoming holidays like Thanksgiving and Christmas.
Ask students to choose books from their classroom library and read silently. Students can also read aloud to partners. Bring a few picture books and novels with you and select an age-appropriate book to read aloud to the class. Have a bank of follow-up activities prepared to fill more time. Pose discussion questions, ask students to draw pictures of their favorite parts or create a class book based on the story.
Fill time using simple art activities that can be completed with materials found in most classrooms. Drawing works well. Ask students to draw pictures of their families, self-portraits or what they think they will look like in 20 years. Have them work in partners and draw each other. Ask students to draw themselves as superheroes and have them describe their powers. Show students how to fold paper to make a grid. Ask them to draw different patterns in each square. If their teacher is ill, have students make get well or welcome back cards for her.